(a) Field of the Invention
The present invention relates to novel phenyl carbamate compounds and pharmaceutical compositions containing the compound. More specifically, the present invention relates to phenyl carbamate compounds and a pharmaceutically acceptable salt thereof, which have a considerably high muscle relaxation effect and low toxicity, and compositions for muscle relaxation containing the compounds and/or pharmaceutically acceptable salt thereof as an active ingredient.
(b) Description of the Related Art
Myotony or spasm is frequently observed as a sequel of cerebrovascular disorders such as stroke or sequel of head injuries, and is not easy to treat.
Myotony, or spasm, is one of skeletal muscle dysfunction diseases due to increase of muscle tone, and caused by central nervous system damage due to various causes such as external injury, cerebrovascular accidents, and the like. The muscle tension is caused by various causes, for example, cervicoomobrachial syndrome which is caused by abnormal posture, fatigue, age-related spine deformity, and the like, and causes spasticity or pain in skeletal muscles of the neck, shoulders, arms, waist, and back; spastic paralysis causing disability of voluntary movement due to muscle hypertonia of hands and feet by disorder of central nervous system such as cerebrovascular disorder; and a combination thereof, thereby resulting in serious hindrances to normal life.
In particular, spastic paralysis is a serious disorder with accompanying symptoms including muscle tension and/or muscular stiffness of hands and feet, difficulty in walking, and the like, thererby causing serious hindrances to normal life. Centrally acting muscle relaxants relieve muscle tension by blocking receptors associated with stimulating muscular function or stimulating receptors associated with inhibiting muscular function, or reducing excessively activated reflex function.
Such centrally acting muscle relaxants may include Methocarbaamol, Chlormezanon, Carisoprodol, Eperisone, Phenprobamide, and the like. However, these drugs act on interneuron of the spinal cord, thereby inhibiting monosynaptic and polysynaptic reflexes, and thus, may cause side effects, such as central nervous inhibition, muscle weakness, and the like.
U.S. Pat. No. 3,313,692 discloses a racemic carbamate compound useful as a therapeutic agent for the central nervous system with decreased side effects compared to cholinergic agent. U.S. Pat. Nos. 2,884,444, 2,937,119, and 3,265,727 suggest dicarbamate compounds useful as therapeutic agents for central nervous system disorders, and U.S. Pat. No. 2,937,119 discloses a N-isopropyl-2-methyl-2-propyl-1,3-propanediol dicarbamate, which was released with the trademark of Soma as a muscle relaxant.
Muscle relaxants are used for improving various symptoms, such as cervicoomobrachial syndrome (shoulder-arm-neck syndrome), lumbago (lower back pain), herniation of intervertebral disk, cerebrovascular disorders, vascular disorders of the spinal cord, spastic spinal paralysis, cervical spondylosis, cerebral palsy, sequelae of injuries (spinal cord injuries, head injuries), spinocerebellar degeneration, multiple sclerosis, amyotrophic lateral sclerosis, and the like, which are associated with muscle spasm involved in musculoskeletal diseases, and also used as an adjuvant to anesthestic agent.
Considering the various and valuable uses of muscle relaxants as aforementioned, development of more effective muscle relaxant is needed.